Synchronizing-clock



C. E. LARRABEE.

SYNCHRONIZING CLOCK.

APPLICATION FILED JULY 10, I919.

Patented Apr. 27, 1920.

UNITED snares Parnnr oFFIoE.

CLINTON E; LARRABEE, F BINGHAMTON, NEW YORK, ASS-IGNOR TO INTERNATIONAL TIME RECORDING COMPANY OF NEW YORK, A CORPORATION OF NEW YORK.

SYNCHRONIZING-CLOOK.

Application filed July 10, 1919.

' is a full, clear, and exact description.

In synchronizing clock systems conforming in details of construction to the drawings and descriptions in numerous prior applications of James V. Bryce, and notably in application Ser. No. 285,813, filed May .21, 1918, the secondary clock mechanisms to be periodically synchronized with a master clock, are capable of running at normal rate, at an accelerated rate and at a retarded rate which may include an actual stoppage of the driving trains, and two electro-magnets are employed which at definite periods, according to the time as indicated by the hands of the secondary, are thrown into a line circuit over which a current is transmitted from or by the master clock for predetermined periods of definite and substantial duration, usually fifteen minutes.

If the secondary be too slow one of the magnets, or that for controlling the means for causing an acceleration in the rate, will be connected up-with and maintained in the then active line circuit for such time as will permit the clock to run ahead until it shows the same time as the master clock, while on the other hand, if the clock be too fast, the other magnet will be, similarly connected with and maintained in the then active line circuit and thereby set in action the. retarding means, causing the clock to stop or slow down until the master clock has caught up to it.

The object of my present invention is to improve upon the above described system by providing means in the secondary clock by which momentary current impulses transmitted from or by the master clock will effeet the same results as the prolonged currents heretofore used, and cause a similar operation of the retarding and the accelerating devices in the secondary clock. It is manifest that the-possibility of effecting the described function of synchronizing by such momentary impulses may be very desirable, and in some cases ofthe greatest practical value.

This improvement I have illustrated in Specification of Letters Patent.

Patented Apr. 27, 1920..

Serial No. 309,950.

the accompanying drawing in which Figure 1 is a diagrammatic illustration of the complete system including both a master and a secondary clock, and Fig. 2 is a sectional view of a well known form of differential gear employed in the secondary.

So far as the primary or master clock,.as well as the train and other essential parts of the secondary are concerned, the construction differs in no essential respects from that commonly employed in systems of this kind. I have therefore shown merely an oscillating circuit breaker 1 and a contact 2 with which it is assumed to come momentarily in engagement at the even hour, as representing the master clock. I have also shown a source of current 3 and a line circuit 4:, which is controlled by such circuit breaker.

The secondary clock, and it will be understood that a plurality of such clocks may be controlled by one master clock, contains an electromagnet 5, included in the line circuit 4, so that it receives a momentary current impulse once every hour and preferably on the even hour. Such impulse will attract the7armatnre 6, carried by a lever 8, pivoted at On the shaft 7 is also a lever 9, turning freely, which carries at its free end a long pawl 10, having a projection 11 with which the end of the armature lever 8 normally engages. The pawl 10 has connected with-it a spiral spring 12 tending to raise it.

The driving clock train 13 carries on its hour shaft a cam 14 with a high point or shoulder 15, and against the periphery of said cam bears a cam wiper 16, pivoted at 17 and forced toward the cam by a spring 18. Said cam wiper has a stop 19, and against this stop the end of pawl 10 is held in contact.

Should the'secondary clock be too slow, theperiodic impulse over the line will energize the magnet 5 and depress the long arm of lever 8 before the cam wiper 16 has reached the shoulder 15, hence the pawl 10 will be drawn down until a shoulder near its upper end comes under a fixed stop 21, locking the pawl in the depressed position and lowering the lever 9. This lever has a tooth or projection 22 which normally engages a ratchet wheel 23, and when it is thus lowered it releases the ratchet and permits it to rotate anti-clockwise. The ratchet controls a fan 24 geared with one of the members 25 of the differential, so that the train runs down rapidly as long as ratchet 23 is free. As soon as the shoulder 15 on cam 14 reaches the point where the cam wiper drops, the lower end of pawl 10 is thrown to the left by the stop 19, its upper end released from the stop 21, and under the action of the spring 12 the lever 9 is caused to engage and arrest the ratchet 23. The secondary clock should at this moment be in exact synchronism with the master clock.

It may benoted that the cam 14 has a second high point 20, but this is merely for the purpose of swinging back the cam wiper. i

Should the secondary clock be too fast then the impulse in magnet 5 will not be received before the cam wiper 16 has reached and dropped from the high point 15. In such event the clock is stopped by the following mechanism: A link 27, drawn v to the right by a spring 28, normally engages a stop 29'on the cam wiper 16. The right hand end of this link carries a pin 26 that lies under the armature lever 8, and in its other end is a slot in which works a pin 30 on an armature lever 31, pivoted at 32 and provided with a retractile spring 33. On the link 27 is a shoulder 34, and the armature lever 31 is normally attracted to a magnet 37 which is supposed to be al.-

ways energized so that the end of the link 27 is held up with the shoulder 34 in line with the end of a lever 35, pivoted at 36, and provided with a retractile spring 38.

hen the cam wiper drops the pin 29 forces the link 27 to the left and by the engagement of the shoulder 34 with the short end of lever 85 the long arm of said lever carries a spring brake 39 into engagement with the periphery of a balance wheel 40., which is in gear with the train 13 through the member 41 of the differential, and the clock is therefore stopped until the even hour when magnet 5 receives an impulse which lowers the long end of lever 8, depressing the end of' the link 27, freeing from engagement therewith the stop .29 and permitting the link to move to the right away from the end of lever 35. Thereupon the spring 38 withdraws the'brake from the balance wheel 40 and the clock immediately starts up again. The stop 29 is again brought into engagement with the link upon the backward movement of the cam wiper effected by the cam point 20.

The electro-magnet 37 is in the circuit of the source 3 at all times and is designed. to be constantly energized. Should the source of this current fail for-any reason the magnet becomes inactive and its armature drops onto a stop 42, lowering the link 27, so that it may no longer engage the lever 35, hence when there is no current on the line the clock runs on normally under the driving influence of itstrain, and is neither accelerated or retarded.

Certain details of construction herein described are important only so far as their function is concerned. For example magnet 5 may be in a normally closed circuit which may be momentarily interrupted with the same results as above described. In such case it is manifest that the use of an independent magnet 37 is not necessary, as the permanent interruption of current in magnet 5 may be utilized to perform the functions of said magnet 37. In other respects the construction may be modified without departure from the invention.

What I claim as my invention is:

1. In a clock synchronizing system the combination with a master clock adapted to send momentary impulses to line at given periods, of a secondary clock capable of a normal rate, an accelerated rate and a retarded rate, of means for effecting the acceleration or retardation, means for bringing into action the accelerating or the retarding means, an electro-magnet in the line for controlling the operation of such means, a cam and a cam wiper cooperating with said magnet in operating said means.

2. In a secondary clock the combination with means for accelerating its rate, of a magnet adapted to receive momentary impulses from a controlling clock at definite periods, an armature for controlling the operation of said accelerating means and set ting the same in operation on the receipt by the magnet of such impulses, a cam and a cam wiper operating in accordance with the time as indicated by the hands of the clock to stop the action of the accelerating means when the secondary has reached synchronism with the primary clock.

3. In a secondary clock the combination with means for retarding its rate, of a cam and cam wiper which controls, according to the time as indicated by the clock, the operation of the retarding means, and an electromagnet and armature adapted to receive momentary current impulses at given periods to restore the retarding means to mmal, an accelerated and a retarded rate, of Q means for controlling the acceleration and the retardation, a magnet and cam cooperating to start and stop-the action of the means for accelerating and retarding the rate for purposes of synchronizing, and anelectromagnet energized at all times While the current is flowing from the source and an armature whichthrows out of operative condition the retarding means upon the failure of such current.

6. In a secondary clock capable of a normal, an accelerated and a retarded rate, of means for controlling the operation of the acceleration and retardation, of an electromagnet adapted to receive momentary impulses at predetermined periods and means operating in accordance with the time as indicated by the hands of the clock and cooperating With the magnet to start and stop theopera tion of the accelerating or the re tarding means according as the clock may be too slow or too fast, and thereby maintain the clock in synchronism with the master clock.

In testimony whereof I hereunto afiix my signature.

CLINTON E. LARRABEE. 

